TWI554691B - Limit shaft structure - Google Patents

Description

Limit shaft structure

A limit rotary shaft structure, especially for a two-page electronic product, allows a double-page electronic product upper cover to be flipped to a limit rotation shaft structure of a bottom cover bottom surface.

According to today's two-page electronic products, such as notebook computers, smart phones, etc., they are composed of a lower cover and an upper cover, and the upper cover of the electronic product can be turned over to the bottom surface of the lower cover, so that the double-page electronic product can be As a tablet computer, in general, this two-page electronic product uses a two-axis shaft device to achieve its 360-degree turning operation. However, the current two-axis shaft device drives the double-page electronic product cover. The movement of the cymbal is mostly after the first rotating shaft is rotated by 180 degrees, and the second rotating shaft is rotated by another 180 degrees to complete the 360-degree turning operation, but this method will cause the upper cover and the lower cover not to be turned over to the upper cover. Will be in the same plane, resulting in damage to the aesthetics of the product; some operators use the connecting rod to drive the first rotating shaft and the second rotating shaft to rotate synchronously, so that when the upper cover is turned to 180 degrees, the upper cover and the lower cover can be in the same plane, but this kind of With the use of the connecting rod, there will be an empty stroke, that is, the first rotating shaft and the second rotating shaft will not rotate synchronously, so the upper cover cannot be stably turned over, and the electronic product tends to be light, thin and short. Also facing relatively reduced, thus downsizing of the process, occurrence of cracks due to the link often than not withstand large forces, can not be used.

The main purpose of the present invention is to use the first limiting device and the second limiting device to cause the first rotating shaft to pivot or the movement of the shaft to bypass the second rotating shaft to smoothly drive the electronic product to cover the upper cover. lift.

In order to achieve the above objective, the creation system is provided with a shaft cylinder, a first rotating shaft, a second rotating shaft, a first limiting device and a second limiting device, wherein: the cylindrical shaft is provided with a first shaft hole and a second shaft hole.

One end of the first rotating shaft is provided with a first shaft portion, the first shaft portion is disposed in the first shaft hole of the shaft barrel, and the other end is provided with a first connecting portion for connecting the upper cover of the electronic product, and the first shaft portion is A first limiting portion is disposed between the first connecting portions, and the first connecting portion and the first limiting portion are exposed to the barrel.

a second shaft portion is disposed at one end of the second rotating shaft, the second shaft portion is disposed in the second shaft hole of the shaft barrel, and the second connecting portion is configured to connect the lower cover of the electronic product, and the second shaft portion is disposed at the other end A second limiting portion is disposed between the second connecting portion and the second connecting portion and the second limiting portion are exposed to the barrel.

The first limiting device is provided with a first cam, a second cam and a first limiting member. The first positioning cam is provided with a first positioning hole, and the first positioning hole is positioned at the first limiting portion of the first rotating shaft. And the first cam outer edge is formed with a first active circle, and the second cam system is provided with a second positioning hole, the second positioning hole is positioned at the second limiting portion of the second rotating shaft, and the second cam outer edge is formed The second limiting circle is disposed, and the first limiting member is disposed between the first cam and the second cam, and the upper and lower ends of the first limiting member respectively abut the first active circle and the second active circle.

The second limiting device is provided with a third cam, a fourth cam and a second limiting member, the third positioning cam is provided with a third positioning hole, and the third positioning hole is positioned at the first limiting portion of the first rotating shaft And the third cam outer edge is formed with a third active circle, and the fourth cam system is provided with a fourth positioning hole, the fourth positioning hole is positioned at the second limiting portion of the second rotating shaft, and the fourth cam outer edge is formed Have a fourth role, and the first The second limiting member is disposed between the third cam and the fourth cam, and the upper and lower ends of the second limiting member respectively abut against the third active circle and the fourth active circle.

1‧‧‧ shaft tube

11‧‧‧First shaft hole

12‧‧‧Second shaft hole

2‧‧‧First shaft

21‧‧‧First shaft

22‧‧‧ First connection

23‧‧‧First Limitation

24‧‧‧First stop

3‧‧‧second shaft

31‧‧‧Second shaft

32‧‧‧Second connection

33‧‧‧Second Limitation

34‧‧‧Second stop

4, 8‧‧‧ first limit device

41, 81‧‧‧ first cam

411, 811‧‧‧ first positioning hole

412, 812‧‧‧ first action circle

413, 813‧‧‧ first highest position

414, 814‧‧‧ first lowest position

42, 82‧‧‧ second cam

421, 821‧‧‧ second positioning hole

422, 822‧‧‧ second action circle

423, 823‧‧‧ second highest position

424, 824‧‧‧ second lowest position

43, 83‧‧‧ First limiter

431, 831‧‧‧ first ontology

432‧‧‧First stop piece

44, 84‧‧‧ First positioning piece

441‧‧‧First pivot hole

442‧‧‧Second pivot hole

443, 843‧‧‧ first displacement slot

444‧‧‧First Limitation Department

5, 9‧‧‧ second limit device

51, 91‧‧‧ third cam

511, 911‧‧‧ third positioning hole

512, 912‧‧‧ third action circle

513, 913‧‧‧ third highest position

514, 914‧‧‧ third lowest position

52, 92‧‧‧ fourth cam

521, 921‧‧‧ fourth positioning hole

522, 922‧‧‧ fourth action circle

523, 923‧‧‧ fourth highest position

524, 924‧‧‧ fourth lowest position

53, 93‧‧‧second limit parts

531, 931‧‧‧ second ontology

532‧‧‧Second stop piece

54, 94‧‧‧Second positioning piece

541‧‧‧The third pivot hole

542‧‧‧4th pivot hole

543, 943‧‧‧ second displacement slot

544‧‧‧Second Limitation

6‧‧‧ Positioning parts

61‧‧‧ fifth pivot hole

62‧‧‧6th pivot hole

63‧‧‧Limited

631‧‧‧First stop surface

632‧‧‧second stop surface

633‧‧‧3rd stop surface

634‧‧‧4th stop surface

7‧‧‧Electronic products

71‧‧‧Upper cover

72‧‧‧Under the cover

The first figure is a perspective view of the present invention.

The second figure is a perspective exploded view of the present invention.

The third figure is a front view of the present invention.

The fourth figure is a cross-sectional view taken along the line A-A of the first figure.

The fifth figure is a cross-sectional view taken along the line B_B of the first figure.

The sixth drawing is a front view of the partial members of the first limiting device and the second limiting device of the present invention.

The seventh figure is a cross-sectional view taken along line C_C of the sixth figure.

The eighth figure is a cross-sectional view taken along the line D_D of the sixth figure.

The ninth figure is a schematic diagram of the three-dimensional action of the present invention (1).

The tenth figure is a schematic view of the front view of the present invention (1).

The eleventh figure is a cross-sectional view taken along the line E_E of the ninth figure.

The twelfth figure is a cross-sectional view taken along line F_F of the ninth figure.

The thirteenth figure is a schematic diagram of the three-dimensional action of the present invention (2).

The fourteenth figure is a schematic view of the front view of the present invention (2).

The fifteenth figure is a sectional view of the G_G line of the thirteenth figure.

Figure 16 is a cross-sectional view of the H_H line of the thirteenth figure.

Figure 17 is a schematic view of the rotation of the present invention.

Figure 18 is a perspective view of another embodiment of the present invention.

Figure 19 is a front elevational view of another embodiment of the present invention.

Figure 20 is a cross-sectional view taken along the line I-I of Figure 18.

The twenty-first figure is a sectional view of the line J_J of the eighteenth figure.

The twenty-second figure is an enlarged view of the K part of the twentieth diagram.

A twenty-third figure is a schematic diagram of a three-dimensional operation of another embodiment of the present invention.

The twenty-fourth embodiment is a schematic view of a front view of another embodiment of the present invention.

The twenty-fifth figure is a cross-sectional view taken along the line L_L of the twenty-third figure.

The twenty-sixth drawing is a sectional view of the M_M line of the twenty-third figure.

Referring to the first to eighth figures, it can be clearly seen from the figure that the present invention is provided with a shaft barrel 1, a first rotating shaft 2, a second rotating shaft 3, a first limiting device 4, and a second limit. The device 5 and the positioning member 6 are provided with a first shaft hole 11 and a second shaft hole 12 in the shaft barrel 1.

A first shaft portion 21 is disposed at one end of the first rotating shaft 2, the first shaft portion 21 is disposed in the first shaft hole 11 of the shaft barrel 1, and the other end is provided to connect the first connecting portion of the upper cover 71 of the electronic product 7. 22, and the first limiting portion 23 is disposed between the first shaft portion 21 and the first connecting portion 22, and the first connecting portion 22 and the first limiting portion 23 are exposed to the shaft barrel 1, and the first limit portion A first stopper portion 24 is convexly provided on one side of the portion 23 .

The second shaft portion 31 is provided with a second shaft portion 31 at one end thereof. The second shaft portion 31 is disposed in the second shaft hole 12 of the shaft barrel 1 and is provided with a second connection for connecting the lower cover 72 of the electronic product 7 at the other end. a second limiting portion 33 is disposed between the second shaft portion 31 and the second connecting portion 32, and the second connecting portion 32 and the second limiting portion 33 are exposed to the shaft barrel 1 and the second limit is A second stopper portion 34 is convexly provided on one side of the seat portion 33.

The first limiting device 4 is provided with a first cam 41, a second cam 42, a first limiting member 43 and a first positioning piece 44. The first positioning piece 44 is respectively provided with a first pivot hole 441 and The second pivot hole 442 is pivotally connected to the first limiting portion 23 of the first rotating shaft 2, and the second pivoting hole 442 is pivotally connected to the second limiting portion 33 of the second rotating shaft 3, and The first positioning piece 44 is disposed with a first displacement groove 443 between the first pivot hole 441 and the second pivot hole 442, and the first displacement groove 443 is concavely disposed with the first limiting portion 444; The cam 41 and the second cam 42 are disposed on the same side of the first positioning piece 44. The first cam 41 is provided with a first positioning hole 411, and the first positioning hole 411 is positioned at the first limiting end of the first rotating shaft 2. 23, and the outer edge of the first cam 41 is formed with a first active circle 412, and the first active circle 412 is respectively provided with a first highest position 413 and a first lowest position 414, and the first highest position 413 is close to the second rotating shaft 3, the second cam 42 is provided with a second positioning hole 421, the second positioning hole 421 is positioned at the second limiting portion 33 of the second rotating shaft 3, and the outer edge of the second cam 42 is formed with a second action circle 422, the second action circle 422 is respectively provided with a second highest position 423 and a second lowest position 424, the second lowest position 424 is close to the first rotation axis 2; and the first limit member 43 is set The first body 431 has a first stop piece 432 extending from the first side of the first body 431. The first stop piece 432 is located in the first limiting portion 444 and can move up and down in the first limiting portion 444. The first body 431 extends from the first displacement groove 443 to the surface of the first positioning piece 44 and is located between the first cam 41 and the second cam 42 , and the first highest position 413 and the second position of the first cam 41 . The second lowest position 424 of the cam 42 is resisted by the upper and lower ends of the first body 431.

The second limiting device 5 is provided with a third cam 51, a fourth cam 52, a second limiting member 53 and a second positioning piece 54. The second positioning piece 54 is respectively provided with a third pivot hole 541 and The fourth pivoting hole 542 is pivotally connected to the first limiting portion 23 of the first rotating shaft 2, and the fourth pivoting hole 542 is pivotally connected to the second limiting portion 33 of the second rotating shaft 3, and The second positioning piece 54 is disposed with a second displacement groove 543 between the third pivot hole 541 and the fourth pivot hole 542, and the second displacement groove 543 is concavely disposed with the second limiting portion 544; and the third The cam 51 and the fourth cam 52 are disposed on the same side of the second positioning piece 54. The third cam 51 is provided with a third positioning hole 511. The third positioning hole 511 is positioned at the first limiting end of the first rotating shaft 2. twenty three, A third active circle 512 is formed on the outer edge of the third cam 51. The third highest position 513 and the third lowest position 514 are respectively disposed at the two ends of the third active circle 512, and the third lowest position 514 is adjacent to the second rotating shaft 3. The fourth cam 52 is provided with a fourth positioning hole 521, the fourth positioning hole 521 is positioned at the second limiting portion 33 of the second rotating shaft 3, and the outer edge of the fourth cam 52 is formed with a fourth acting circle 522, A fourth highest position 523 and a fourth lowest position 524 are respectively disposed at the two ends of the four-acting circle 522. The fourth highest position 523 is adjacent to the first rotating shaft 2; and the second limiting member 53 is provided with the second body 531. A second stop piece 532 is defined on the two sides of the second body 531. The second stop piece 532 is located in the second limiting portion 544 and can move up and down in the second limiting portion 544, and the second body 531 is The second displacement groove 543 extends out of the surface of the second positioning piece 54 and is located between the third cam 51 and the fourth cam 52, and the third lowest position 514 of the third cam 51 and the fourth highest position of the fourth cam 52 The 523 is abutted against the upper and lower ends of the second body 531.

The positioning member 6 is disposed on the side of the second limiting device 5, and the second pivoting hole 61 and the sixth pivoting hole 62 are respectively disposed at the two ends of the positioning component 6, and the fifth pivoting hole 61 is pivotally connected to the first The first limiting portion 23 of the rotating shaft 2, the sixth pivoting hole 62 is pivotally connected to the second limiting portion 33 of the second rotating shaft 3, and the positioning member 6 is disposed between the fifth pivoting hole 61 and the sixth pivoting hole 62. A limiting portion 63 is formed on one side of the upper portion, and a first stopping surface 631 and a second stopping surface 632 are respectively formed on two sides of the upper end of the limiting portion 63, and a third stopping surface is formed on each of the two sides of the lower end 633 and the fourth stop surface 634 , and the first rotating shaft 2 is convexly disposed on the first limiting portion 23 side with a first stopping portion 24 , and the first stopping portion 24 is located at the first stop of the limiting portion 63 . Between the surface 631 and the second stop surface 632, the second rotation shaft 3 is convexly disposed on the second limiting portion 33 side with a second stopping portion 34, and the second stopping portion 34 is located at the limiting portion 63. Between the three stop faces 633 and the fourth stop faces 634.

Referring to the first, fourth, fifth and ninth to seventeenth, as can be seen from the fourth and fifth figures, the third cam 51 of the second limiting device 5 The third lowest position 514 and the fourth highest position 523 of the fourth cam 52 abut against the second body 531 of the second limiting member 53, that is, the distance between the third lowest position 514 and the fourth highest position 523 is equal to The distance between the upper and lower ends of the second body 531 is such that the third cam 51 and the fourth cam 52 are in a state of restricting rotation, and the first limiting device 4 The first highest position 413 of the first cam 41 abuts the upper end of the first body 431, and the lower end of the first body 431 abuts against the second lowest position 424 of the second cam 42 away from the second highest position 423 The other side, that is, the second cam 42 is deflected by the second lowest position 424 away from the second highest position 423 by an angle θ, so that the second cam 42 produces a rotatable state of θ angle; see ninth to tenth As shown in FIG. 7 , when the user flips over the upper cover 71 of the electronic product 7 , the third lowest position 514 and the fourth highest position 523 of the second limiting device 5 abut against the second body of the second limiting member 53 . The 531 is in a state of restricting rotation, and the second cam 42 of the first limiting device 4 has a rotatable state of a θ angle. Therefore, when the user flips over the upper cover 71 of the electronic product 7, the second cylinder 1 is driven first. The rotating shaft 3 pivots to drive the first limiting member 43 of the first limiting device 4 to pivot according to the second rotating shaft 3, and when the shaft cylinder 1 is rotated to the lower end of the first limiting member 43 against the second cam 42 At the second lowest position 424, the first limiting device 4 will assume a rotating state, and due to the axis At the same time, the second limiting member 53 of the second limiting device 5 is driven by the second rotating shaft 3, and the second limiting member 53 is moved from the fourth highest position 523 of the fourth cam 52 toward the fourth lowest position 524. The direction of movement, that is, the distance between the third action circle 512 and the fourth action circle 522 is gradually decreased, so that the second limit device 5 is changed from the limit rotation state to the free rotation state, when the first limit device 4 is limited. After the position state, since the user will continue to push the upper cover 71, the first rotating shaft 2 is rotated to pivot the first cam 41 from the first highest position 413 toward the first lowest position 414, since the first cam 41 is Pivoting from the first highest position 413 toward the first lowest position 414, the distance between the first active circle 412 and the second active circle 422 is gradually opened, and further greater than the distance between the upper and lower ends of the first body 431, so that A limiting device 4 is switched from the limit state to the free state, and when the first rotating shaft 2 rotates, the third cam 51 of the second limiting device 5 is also driven to pivot according to the rotating direction of the first rotating shaft 2, at this time The third cam 51 is directed from the third lowest position 514 toward the third highest position 513 Pivoting, so the distance between the third action circle 512 and the fourth action circle 522 is gradual, so that the third lowest position 514 of the third cam 51 and the fourth highest position 523 of the fourth cam 52 are resisted by the second The body 531 has two upper and lower ends, and the third lowest position 514 and the fourth highest position 523 are resisted by the second After the upper and lower ends of the body 531, the second limiting device 5 is in a limit state, so that the second rotating shaft 2 cannot continue to rotate; as shown in FIG. 17, repeating the above steps, the upper cover 71 can be driven and turned to The bottom surface of the lower cover 72.

Referring to FIG. 18 to FIG. 26, it can be clearly seen from the figure that the third lowest position 914 and the fourth position of the third cam 91 of the second limiting device 9 according to another embodiment of the present invention. When the fourth highest position 923 of the cam 92 is at the beginning, the distance is greater than the distance between the upper and lower ends of the second body 931. Therefore, a gap is generated between the third cam 91 and the second body 931, so that the second limiting device 9 is formed. In a freely rotating state, the first highest position 813 of the first cam 81 of the first limiting device 8 and the second lowest position 824 of the second cam 82 are initially equal to the upper and lower ends of the first body 831. Therefore, the first highest position 813 and the second lowest position 824 are resisted by the upper and lower ends of the first body 831, so that the first limiting device 8 is in a limited rotation state, whereby the user flips the electronic product 7 When the upper cover 71 is used, since the first highest position 813 and the second lowest position 824 of the first limiting device 8 are resisted to form a limit shape on the upper and lower ends of the first body 831, the first cam 81 is limited only by the first A highest position 813 is rotated toward the first lowest position 814 for the user to turn over When the product 7 is over the cover 71, the first rotating shaft 2 is rotated, and is pivoted by the first highest position 813 toward the first lowest position 814, since the first cam 81 is directed from the first highest position 813 toward the first lowest position 814. The direction pivots to make the distance between the first active circle 812 and the second active circle 822 gradually open, and is greater than the distance between the upper and lower ends of the first body 831, so that the first limiting device 8 is changed from the limit state to the free state. When the first rotating shaft 2 rotates, the third cam 91 of the second limiting device 9 is also pivoted according to the rotating direction of the first rotating shaft 2, and the third cam 51 is directed to the third by the third lowest position 914. The highest position 913 pivots, so the distance between the third active circle 912 and the fourth active circle 922 is progressive, and the third lowest position 914 of the third cam 91 is offset from the fourth highest position 923 of the fourth cam 92. Holding the upper and lower ends of the second body 931, and the third lowest position 914 and the fourth highest position 923 are resisted by the upper and lower ends of the second body 931, the second limiting device 9 is in a limit state, so that the second rotating shaft 2 can't continue to rotate, because the user will continue to push up 71, therefore, i.e. the shaft tube 1 will be pivoted by the second shaft 3, so as to drive the second stop means 9 of the second stopper member 93 by the second rotary shaft 3, by the fourth cam 92 of the fourth highest bit The position 923 moves toward the fourth lowest position 924, so that the distance between the third action circle 912 and the fourth action circle 922 is gradually decreased, and the second limit device 9 is changed from the limit state to the free state, and the shaft barrel is 1 when the second rotating shaft 3 pivots, the first limiting member 83 of the first limiting device 8 is moved by the second lowest position 824 of the second cam 82 toward the second highest position 823, so that the first acting circle 812 and The distance between the second active circle 822 is gradual, so that the first highest position 813 and the second lowest position 824 are resisted by the upper and lower ends of the first body 831, so that the first limiting device 8 forms a limit state, the shaft barrel 1 That is, the second limiting device 9 can be driven by the first limiting device 8 after the first limiting device 8 forms the limiting state, because the user will continue to push the upper cover 71, thereby driving the first rotating shaft 2 to rotate. The free state changes to the limit state, and the first limiting device 8 changes from the limit state to the free state. Repeating the above steps, the upper cover 71 can be driven and turned to the bottom surface of the lower cover 72.

Therefore, the present invention can solve the deficiencies and shortcomings of the prior art, and can improve the efficiency, and the key technologies are further:

(1) The present invention uses the first limiting device 4 and the second limiting device 5 to interact in a limited state and a free state, so that only the first rotating shaft 2 rotates or the shaft cylinder 1 rotates according to the second rotating shaft 3 at the same time. The displacement, in turn, can accurately control the range of rotation and the order, so that when the upper cover 71 is turned 180 degrees, it can be horizontal with the lower cover 72, and the upper cover 71 and the lower cover 72 can be accurately closed or overlapped.

(2) Since the present invention utilizes the first cam 41, the second cam 42, the third cam 51, and the fourth cam 52 to form a limit rotation, it can withstand a large external force, and is less prone to breakage or damage. .

1‧‧‧ shaft tube

2‧‧‧First shaft

22‧‧‧ First connection

24‧‧‧First stop

3‧‧‧second shaft

32‧‧‧Second connection

34‧‧‧Second stop

4‧‧‧First limit device

41‧‧‧First Cam

42‧‧‧second cam

44‧‧‧First positioning piece

5‧‧‧second limit device

51‧‧‧ Third Cam

52‧‧‧4th cam

54‧‧‧Second positioning piece

6‧‧‧ Positioning parts

63‧‧‧Limited

631‧‧‧First stop surface

633‧‧‧3rd stop surface

634‧‧‧4th stop surface

Claims (6)

A limit rotation shaft structure is provided with a shaft cylinder, a first rotation shaft, a second rotation shaft, a first limiting device and a second limiting device, wherein: the shaft cylinder is provided with a first shaft hole and a second shaft hole a first shaft portion is disposed at one end of the first shaft, the first shaft portion is disposed in the first shaft hole of the shaft cylinder, and the first limiting portion is disposed on one side of the first shaft portion, and the first limit portion is The second portion of the second shaft is provided with a second shaft portion, the second shaft portion is disposed in the second shaft hole of the shaft barrel, and the second shaft portion is provided with a second limiting portion And the second limiting portion is exposed to the shaft cylinder; the first limiting device is provided with the first cam, the second cam and the first limiting member, and the first cam system is provided with the first positioning hole, the first positioning The hole system is positioned on the first limiting portion of the first rotating shaft, and the first cam outer edge is formed with a first active circle, and the second cam system is provided with a second positioning hole, and the second positioning hole is positioned at the second rotating shaft a second limiting portion, and the second cam outer edge is formed with a second active circle, and the first limiting member is disposed between the first cam and the second cam, The upper and lower ends of the first limiting member respectively abut the first active circle and the second active circle; the second limiting device is provided with a third cam, a fourth cam and a second limiting member, and the third cam system is disposed The third positioning hole is located at the first limiting portion of the first rotating shaft, and the third cam outer edge is formed with a third active circle, and the fourth cam system is provided with a fourth positioning hole, and the fourth The positioning hole is positioned on the second limiting portion of the second rotating shaft, and the fourth cam outer edge is formed with a fourth active circle, and the second limiting member is disposed between the third cam and the fourth cam, and the second The upper and lower ends of the limiting member respectively abut against the third active circle and the fourth active circle. The limit shaft structure according to claim 1, wherein the first working circle and the first lowest position of the first working circle of the first cam are respectively disposed. The first highest position is close to the second rotating shaft, and the second working circular second end of the second cam is respectively provided with a second highest position and a second lowest position, and the second lowest position is close to the first rotating shaft, so that the first The upper and lower ends of the limiting member respectively abut the first highest position and the second lowest position. The limit shaft structure according to claim 1, wherein the third working circle has a third highest position and a third lowest position, and the third lowest position is adjacent to the second rotating shaft. The fourth working circle of the fourth cam is respectively provided with a fourth highest position and a fourth lowest position, and the fourth highest position is close to the first rotating shaft, so that the upper and lower ends of the second limiting member respectively abut against the third end The lowest position and the fourth highest position. The first position limiting device is provided with a first positioning piece, and the first positioning piece is respectively provided with a first pivot hole and a second pivot hole, respectively. The first pivoting hole is pivotally connected to the first limiting portion of the first rotating shaft, the second pivoting hole is pivotally connected to the second limiting portion of the second rotating shaft, and the first positioning piece is in the first pivoting hole and the first positioning hole A first displacement slot is disposed between the two pivot holes, and the first displacement slot is provided with a first limiting portion, and the first limiting member is provided with a first body, and the first body has two sides extending a stop piece, the first stop piece is located in the first limiting portion, and is movable up and down in the first limiting portion, and the first system extends from the first displacement groove to the surface of the first positioning piece, and The first action circle of a cam and the second action circle of the second cam abut against the upper and lower ends of the first body. The second limiting device is provided with a second positioning piece, and the second positioning piece is respectively provided with a third pivot hole and a fourth pivot hole, respectively. The third pivoting hole is pivotally connected to the first limiting portion of the first rotating shaft, the fourth pivoting hole is pivotally connected to the second limiting portion of the second rotating shaft, and the second positioning piece is connected to the third pivoting hole and the third positioning hole a second displacement groove is disposed between the four pivot holes, and the second displacement groove is provided with a second limiting portion, and the second limiting member is provided with a second body, A second stop piece extends from the two sides of the second body, the second stop piece is located in the second limiting portion, and is movable up and down in the second limiting portion, and the second system extends from the second displacement groove Second, the surface of the sheet is positioned, and the third active circle of the third cam and the fourth active circle of the fourth cam are abutted on the upper and lower ends of the second body. The limit shaft structure of claim 1, wherein the second limiting device is provided with a positioning member, and the second end of the positioning member is respectively provided with a fifth pivot hole and a sixth pivot hole, and The fifth pivoting hole is pivotally connected to the first limiting portion of the first rotating shaft, the sixth pivoting hole is pivotally connected to the second limiting portion of the second rotating shaft, and the positioning member is disposed at the fifth pivoting hole and the sixth pivoting hole A limiting portion is convexly disposed on one side thereof, and a first stopping surface and a second stopping surface are respectively formed on two sides of the upper end of the limiting portion, and a third stopping surface and a fourth portion are respectively formed on two sides of the lower end a first stop portion is disposed on a side of the first limiting portion, and the first stopping portion is located between the first stopping surface and the second stopping surface of the limiting portion. The second rotating shaft is convexly disposed on the second limiting portion side with a second stopping portion, and the second stopping portion is located between the third stopping surface and the fourth stopping surface of the limiting portion.